LMR-120 · Cosmology
Hubble Tension
Two ways to measure the universe's expansion. They don't agree. Nobody knows why.
§ A first look
§ Depths
Six ways into the same idea — from bedtime story to chalkboard. No order required.
L1 · Crayon
Told like a bedtime story.
For a curious 10-year-old. No jargon. Just a picture in your head.
The universe is getting bigger. We can measure how fast in two completely different ways. One way looks at the leftover heat from the Big Bang and works backwards. The other way looks at nearby exploding stars and works outwards. The two answers don't match. They should. We've checked. We've re-checked. We've re-re-checked. They still don't match. Something basic in our story is missing. Or somebody made a small mistake. Either way, very interesting times for cosmologists.
§ Strange but true
- 01The universe is stranger than your intuition. This is a rule, not an exception.
- 02Every fact in physics was once an outrageous guess. Most still feel like one.
- 03If it doesn't bend your brain a little, you haven't read it carefully enough.
§ From the field journal
Hubble Tension
"Two ways to measure the universe's expansion. They don't agree. Nobody knows why."
— observed, sketched, not yet fully understood.
§ Nearby
Constellations near Hubble Tension
→
CMB
The afterglow of the Big Bang, still arriving 13.8 billion years later.
→
Redshift
The universe is stretching, and dragging every wavelength of light with it.
→
Dark Energy
Something is pushing space apart faster, and we have no idea what.
→
Inflation
In 10⁻³² seconds, the universe grew by a factor of 10²⁶.
→
Big Bang
Not an explosion in space. An expansion of space.